High voltage switching device



Nom-9, 1937. R. R. PxTTMAN ET A1.

HIGH VOLTAGE SWITCHING DEVICE Filed Sep'i.. 25, 1936 I l P ATTORNEY 35 In the description of Patented Nov. 9, 1937 UNITED STATES PATENT OFFICE Ralph R. Pittman and Carroll B. Walsh, Pine Bluil, Ark.

Application September 25, 1936, Serial No. 102,581

Claims.

This invention relates generally to switching equipment for use in connection with electrical circuits, and particularly to those devices known as high tension air-break switches.

'I'he present invention is an improvement upon the construction shown in our United States Patent 1,963,413, dated June 19, 1934, for Arc suppressing air break switch.

Among the objects of the present invention may be noted (a) the provision ox' means for transferring an open-air circuit interrupting arc Vto a restricted path within a tubular insulator,

and subsequently elongating the arc therein; (b) the provision of means for confining the arc during the stretching process within an annular space bounded by insulating materiali (c) the provision of gas evolving insulating material for bounding the arc space to assist in arc extinguishment; (d) the provision oi' an arc suppressor so combined with a conventional airbreak switch that the operation of the latter in the conventional manner automatically eiiects the proper functioning of the arc suppressor; (e) the provision of an eilective and inexpensive arc vsuppressor and switching device which is simple in operation and construction.

With the above and other objects in View which appear as the description proceeds, our invention comprises the elements and combinations of elements, features of construction and arrangement of parts which will be exemplified in the structures herein described, and the scope of the invention will be indicated in the appended claims.

the embodiment of the invention here presented, speciiic language will be used for the purpose of facilitating an understanding of its construction and operation, but it will be understood that various changes in 4o the speciiic construction may be made without departing from the principles of the invention.

In the drawing: Fig. l is a side elevational view of the switching device.

Fig. 2 is a sectional view of the arc suppressor embodied in the switching device, taken along the plane indicated by the line II-II in Fig. 3.

Fig. 3 is a side elevational view of the suppressor, shown in section.

Fig. 4 is a front view of the arc suppressor, shown partly in section.

Fig. 5 is another sectional view of the arc suppressor, taken along the plane V-V in Fig. 4. Referring iirst in detail to the arc suppressor,

as illustrated by Figs. 2, 3, 4, and 5, a rod-like (Cl. 20G- 146) supporting Imember 24 is mvotally mounted at the lower end thereof, by means of the suppressor pivot 45, on the mounting channel 23. The latter is provided with the holes 46, through `which suitable fasteners may be passed in order to rigidly mount the device on the top oi.' an insulator, as shown in Fig. l. To the upper end portion of the member 24, and extending coaxially upwardly therefrom, is secured, by means ot cooperating threads, the cylindrical element of insulating material 28. A suitable material for the latter is hard liber.

An elongated metal cap 3l is loosely ntted over the element 28, and is provided with screw threads at the lower end portion engaging cooperating threads on the ber tube 21. The elements 30 and 2l provide a housing for the element 2B and the member 24, being disposed in substantial coaxial relation therewith. A lower tube ring 36 is`threaded on the lower end portion of the tube 21. The housing, including the hollow cap member 3l and the hollow tubular insulator 21,'is arranged for reciprocatory moven ment with respect to the member 24 and the element 28, and is guided and limited in its reciprocations by means of the guide screw 26, extending laterally through the lower ring 36 into the longitudinally extending slot 25 of the member 24.

A compression spring 32, one end of which abuts the inner surface of the top of thev cap 30, and the other end oi' which abuts the filler of insulating material 2l within the element 28,

` is continuously urging the housing outwardly away from the mounting channel 23. For preventing such movement of the housing until desired, a latch member 4l removably connects the lower tube ring 36 to the mounting channel 23. The ring 36 is provided with a pair of integral, laterally extending spaced ears 3l. between which is mounted the latch roller pin 38, and the latch roller I9. The -upper end portion of thelatch member 4l is arranged to hook over the roller 3l, and the lower end is pivotally mounted on the mounting channel 23 by means o! the latch member pivot 4l. A latch spring 42 continuously bias the latch member 40 in a direction to maintain the latched position.

It should be noticed that the supporting member 24, together .with all the elements supported thereby, may be rotated in a counterclockwise direction, as viewed in Fig. 3, about the pivot 45. Such movement is normally prevented by the alignment spring 43. one end of which is attached to the mounting channel 33, and the otherto the pin dii, the latter being rigidly secured to the supporting member 23.

It will also be seen that the above mentioned counter-clockwise movement will release the housing from the latch member 33, and permit it to move upwardly away from the mounting channel 23 under the inuence of the actuating spring 32. The latter movement telescopes the tubular insulator 2l with respect to the insulating element 23. The position of the various members after this movement is illustrated by Fig. t.

Referring again to Fig. 3, the upper end of the supporting member 23 is provided with an enlarged portion 33, of slightly less diameter than the internal diameter of the tube 2li. A ring 33, of slightly larger diameter than that of the portion 33 of the supporting member 33, is supported at the upper end of the tube 2i, and arranged to move therewith. In the closed position, illustrated by Fig. 3, the ring 3d is urged to engagement with the portion 33 by means of the movable contact spring 33, so that the metal cap 3@ is electrically connected through the spring 35 and the ring 3ft `to the supporting member 23.

With this arrangement, a voltage impressed upon the suppressor between the triangularly shaped lateral extension 3i of the cap 30, and the mounting channel 33, will result in a flow of current through the cap 30, the contact spring 35, the movable contact 34, the stationary contact 33, the supporting member 3ft, and thel pivot 33 to the mounting channel 33.

Under such a condition, if the extension 3i is urged in a counter-clockwise direction to release the housing from the latch member d0, a circuit interrupting. arc will beformed between the stationaryv arc suppressing contact 33 and the movable arc suppressing contact 33, as the latter moves with the housing away from the former. This arc is therefore elongated within the annular space between the inner surface of the tube 3l! and the outer surface ofthe element 33. ,'llh'e arc is thus elongated in a space in which the cross-sectional area may be changed without changing the degree of proximity of the arc with the insulating material bounding the arc space. We have found this arrangement to be an unexpectedly eective arc extinguishing structure for example, under test, substantially zero power factor 60 cycle alternating currents at 8000 volts have been broken with only 11/2 inches of arc elongation in a device having a one-inch diameter And an annular space of approximately one thirtysecond of one inch. This is about six times as effective as the conventional expulsion fuse tube now in general use. For best results, the arrangement should 'be such that the spring 32 will quickly actuate the device to the open position. The gases resulting from the action of the arc upon the element 20 and the tube 23 are highly conductingin character, and are therefore vented from the open end of the tube 29 in a direction away from the live parts.

Fig. 1 illustrates our switching device, in which the above described arc suppressor is embodied. The line conductors 20 and 2l respectively terminate at the top of the insulators l l and l2, the latter being supported in any suitable manner at the respective ends of the mounting base lll. An intermediate insulator i3, arranged to be rocked to and fro in response to movement of the crank arm i5, is connected at the topto the conductor 20 through the pantograph i3. rlhe arrangement just described is not new, and of itself, is not the present invention.

`A stationary contact il, secured to the insulator i l, cooperates with the movable contact i3, secured to the rockable insulator I3, to provide the contacts of a main current carrying switch. The stationary contact il is provided with an upwardly extending arcing horn l0, and the latter cooperates with the arcing horn i3 oi the movable contact i3. The arcing horns just referred to perform their well known function of preventing the burning and consequent pitting of the contacts.

The arc suppressor, constructed as above described, and designated in its entirety in Fig. l by the numeral iii, is rigidly secured, in any suitable manner, to the top of the insulator lli with its mounting channel in electrical contact with the contact ill, and so that it extends upwardly in the direction of movement of the arcing horn i3. is the crank arm iii is rotated, the contacts [13 and ill iirst part, and the circuit interrupting arc is initially drawn between the arcing horns i3 and i3. .as the opening movement continues, the arcing horn |13 engages the cap extension 3i, and the path of the current is`then through the arc suppressor 33, which immediately extinguishes the arc previously existing between the arcing horns IB and i3. A continued opening movement of the crank arm i3 causes the arcing horn I3 to unlatch the arc suppressor, in which the circuit interrupting arc is extinguished, as before described. The broken lines in Fig. l illustrate the position of the members when the switching device is in the open position. An upwardly extending integral portion of the movable contact i3 is provided for engaging the outer end of the arc suppressor 23 as the switching device is closed, thusurging the housing of the arc suppressor to the latched position against the bias of the actuating spring 33.

The advantage of the movable housing will be apparent from the fact that this housing forms a part of the arc extinguishing mechanism, avoiding the necessity for a separate housing. lit may also be noted that the failure of the are suppressoir will not render the current carrying switch useless; as the arrangement is such that the latter may always be used in the customary manner.

We claim as our invention: ll. In combination, elements constituting a current carrying switch 'including a stationary insulator, a movable insulator, and separable con-1 tacts carried thereby, an arc suppressor swingably mounted on said stationary insulator, said arc suppressor including a cylindrical element of `.insulating material and a hollow tubular insulator arranged for telescopic movement with respect to said cylindrical element, separable arc suppressing contacts secured respectively to said element and said tubular insulator, latch means maintaining and resilient means opposing the engagement of said arc suppressing contacts, and means cooperating with said movable insulator for swinging said arc suppressor 'about its mounting tcA ment o1' insulating material, arc suppressing contacts secured respectively to said element and said hollow insulator, movable means for actuating said movable insulator, means responsive to a movement of said movable means in a direction to engage said separable contacts for engaging said arc suppressing contacts, latch means maintaining said arc suppressing contacts in engagement, resilient means urging the arc suppressing contacts to disengagement and the tubular insulator to the telescoped position with respect to the element of insulating material, and means responsive to a movement of said movable means in a direction to disengage said separable contacts for swinging said arc suppressor about its mounting, whereby said latch means is released.

3. In combination, elements constituting a current carrying switch including a pair of relatively movable insulators and separable contacts carried thereby, an arc suppressor swingably mounted on one of said insulators, said arc suppressor including a cylindrical element of insulating material and a hollow tubular insulator arranged for telescopic movement with respect to said cylindrical element, separable arc suppressing contacts secured respectively to said element and said tubular insulator, latch means maintaining and resilient means opposing the engagement of said arc suppressing contacts, and means cooperating with the other oi' said insulators for swinging said arc suppressor about its mounting for unlatching said tubular insulator and disenpressor including a cylindrical element of gas evolving insulating material and a'h'ollow tubular insulator arranged for telescopic movement with respect to said cylindrical element, separable arc suppressing contacts secured to said element and said tubular insulator respectively, latch means maintaining and resilient means opposing l the engagement of said arc suppressing contacts, and means cooperating with the other of said insulators for swinging said arc suppressor about its mountingv for unlatching said tubular insulator and disengaging said arc suppressing contacts.

5. The structure recited in claim 4, said hollow tubular insulator having gas evolving material disposed on the inner surface thereof.

RALPH R. PITTMAN. CARROLL H. WALSH. 

